A microgrid is a localized grouping of interconnected electricity sources (e.g., distributed renewable energy resources) and loads that normally operate connected to, and synchronous with, the traditional centralized grid (macrogrid), but can disconnect and function autonomously as physical and/or economic conditions dictate. A microgrid exists within clearly defined electrical boundaries and acts as a single controllable entity with respect to an external distribution power macrogrid. Microgrids are typically comprised of energy generating/consuming resources such as natural gas turbines, wind turbines, photovoltaic (PV) cells, combined heat and power (CHP) units, diesel generators, energy storage systems (e.g., batteries, flywheels, etc.), electric vehicles (EV), fuel cells, etc.
A microgrid may continuously operate in either grid connected mode or island mode. The most salient feature of a microgrid is its ability to isolate itself from the distribution power macrogrid when the distribution power macrogrid is experiencing disturbances or blackouts, thereby seamlessly transitioning to islanded mode operation.
With the use of distributed generation including renewable generation, a significant reduction of carbon dioxide emissions can be achieved as well. Hence, microgrids can maximize the benefits of “clean” distributed generation and supply electricity to its load during power outages of the distribution power grid.
Like traditional control centers equipped with Energy Management Systems (EMS), a microgrid can be empowered by a MicroGrid Management System (MGMS). The MGMS is a programmed, networked computer system, including sensors and actuators, that is responsible for monitoring the microgrid's generation, load, connectivity to the distribution power grid, interchange with the distribution power grid, and its voltage level. In addition, the MGMS can be responsible for taking required control actions to maintain power balance, following desired interchange requirements, maintaining voltage within a desired range, achieving optimal economics, and respecting emission constraints.
Conventionally, most of these tasks are performed by a key EMS component called the Automatic Generation Control (AGC) application suite. These tasks are typically coordinated in real-time via human intervention by dispatchers monitoring the power grid on a 24 hours per day, 7 days a week (24×7) basis. In contrast, a microgrid equipped with a MGMS would ideally function seamlessly in an unsupervised manner under various conditions without dedicated operators having to continuously monitor the microgrid to take control actions.
Thus, there is a need to enable the MGMS with the capability of continuously evaluating the microgrid's operating conditions, and automatically implementing desired control actions in a timely manner when necessary, thereby alleviating the need for a 24×7 operator monitoring or controlling the system. Therefore, what is needed are systems, methods and apparatus for improved generation control of microgrid energy systems.